Timer in a windowless component (MFC-VS2010)

Hi, 

I try to insert a timer event in a windiwless component (derived from CCmdTarget) and I don't know how.

I tried to change the baseclass from CCmdTarget to  CWnd and then I got the opportunity to add a WM_TIMER procedure.

But the software assert in the call of SetTimer() and never go into the OnTimer().

Can anybody help me?

Thanks

Bernard